What Is Resolver?

Resolver is a kind of electromagnetic sensor, also known as synchronous resolver. It is a small AC Angle measuring motor used to measure the angular displacement and angular velocity of rotating objects. It consists of a spindle and a rotor. As the primary side of the transformer, the spindle winding receives the excitation voltage, and the excitation frequency is usually 400, 3000, and 5000HZ. As the secondary side of the transformer, the rotor winding obtains the induced voltage through electromagnetic coupling. The working principle of resolver is basically similar to that of ordinary resolver. The difference is that the primary and secondary windings of ordinary resolver are relatively fixed, so the ratio of output voltage to input voltage is constant, while the primary and secondary windings of resolver change their relative positions with the angular displacement of the rotor. Therefore, the output voltage varies with the rotor angular displacement, and the voltage amplitude of the output winding has a sine or cosine function relationship with the rotor Angle, or maintains a proportional relationship with the Angle within a certain Angle range, or a linear relationship. resolver can be used to transmit Angle or electrical signals in synchronous servo systems and digital servo systems. It can be solved as a function in a solving device, so it is also called a solver.

resolver generally has two structural forms: bipolar winding and quadrupole winding. The main shaft and rotor of the resolver with bipolar winding have a pair of magnetic poles, and the quadrupole winding has two sets of magnetic poles, which are mainly used for high-precision detection systems. In addition, there is a multipole resolver for high-precision absolute detection systems.

Classification of resolvers

According to the functional relationship between output voltage and rotor Angle, resolver has three main categories:

1. The output voltage of sine-cosine resolver---- is the sine or cosine function of the rotation Angle function of the rotor.

2. Linear resolver---- The output voltage is a linear function of the rotor Angle. Linear rotating transformers are divided into two types according to rotor structure: hidden pole type and convex pole type.

3. Ratio resolver---- The output voltage is proportional to the Angle.

Application of resolver

resolver is a precision Angle, position, speed detection device, suitable for all the use of rotary encoders, especially high temperature, cold, wet, high speed, high vibration and other rotary encoder can not work properly. Due to the above characteristics of resolver, it can completely replace the photoelectric encoder, and is widely used in servo control system, robot system, mechanical tools, automobile, electric power, metallurgy, textile, printing, aerospace, shipbuilding, weapons, electronics, metallurgy, mining, oil field, water conservancy, chemical industry, light industry, construction and other fields of Angle and position detection system. It can also be used for coordinate transformation, trigonometric and angular data transmission, and as a two-phase phase shifter for angular digital conversion devices.